| Autor: |
Hasan R; Department of Chemistry, Rutgers University - Newark, Newark, New Jersey 07102, United States., Aslam HZ; Department of Chemistry, Rutgers University - Newark, Newark, New Jersey 07102, United States., Hewage NW; Department of Chemistry, Columbia University, New York, New York 10027, United States., Soto E; Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.; Ames National Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States., Lalancette RA; Department of Chemistry, Rutgers University - Newark, Newark, New Jersey 07102, United States., Akopov G; Department of Chemistry, Rutgers University - Newark, Newark, New Jersey 07102, United States. |
| Abstrakt: |
In this study, we present the growth of large Ln 3 (SiS 4 ) 2 I ( Ln = La, Ce) crystals, both undoped and doped with Ce and Eu. The synthesis process involves the utilization of an arc-melted precursor in conjunction with sulfur and KI. We investigate the role of Zr, Nb, Mo, and Ir as cocrystallization agents, facilitating the growth of relatively large (up to 6-7 mm) crystals. Our study suggests that Mo effectively acts as a cocrystallization agent for the synthesis of the Ln 3 (SiS 4 ) 2 I and Ce- and Eu-doped La 3 (SiS 4 ) 2 I phosphors. We confirmed the phase purity and crystal structure through powder XRD and single-crystal XRD analyses. The Ce- and Eu-doped compositions exhibit broad-spectrum transitions from UV to visible regions. Photoluminescence spectroscopy analysis reveals distinct emission bands for Ce-doped La 3 (SiS 4 ) 2 I at 430 and 490 nm within the bluish region (0.15, 0.22 coordinates on the 1931 CIE chromaticity diagram) upon excitation at 375 nm. Conversely, Eu-doped La 3 (SiS 4 ) 2 I demonstrates an emission band at 578 nm in the yellow-orange (0.45, 0.51) region following excitation at 450 nm. Analysis of time-resolved spectra indicates multiple emissive bands contributing to the photoluminescence spectra. The average half-life of emission bands suggests fluorescence for (La 1- x Ce x ) 3 (SiS 4 ) 2 I and phosphorescence for (La 1- x Eu x ) 3 (SiS 4 ) 2 I phosphors. |
